/**
 * Software License, Version 1.0
 * 
 * Copyright 2003 The Trustees of Indiana University.  All rights reserved.
 * 
 *
 *Redistribution and use in source and binary forms, with or without 
 *modification, are permitted provided that the following conditions are met:
 *
 *1) All redistributions of source code must retain the above copyright notice,
 * the list of authors in the original source code, this list of conditions and
 * the disclaimer listed in this license;
 *2) All redistributions in binary form must reproduce the above copyright 
 * notice, this list of conditions and the disclaimer listed in this license in
 * the documentation and/or other materials provided with the distribution;
 *3) Any documentation included with all redistributions must include the 
 * following acknowledgement:
 *
 *"This product includes software developed by the Community Grids Lab. For 
 * further information contact the Community Grids Lab at 
 * http://communitygrids.iu.edu/."
 *
 * Alternatively, this acknowledgement may appear in the software itself, and 
 * wherever such third-party acknowledgments normally appear.
 * 
 *4) The name Indiana University or Community Grids Lab or NaradaBrokering, 
 * shall not be used to endorse or promote products derived from this software 
 * without prior written permission from Indiana University.  For written 
 * permission, please contact the Advanced Research and Technology Institute 
 * ("ARTI") at 351 West 10th Street, Indianapolis, Indiana 46202.
 *5) Products derived from this software may not be called NaradaBrokering, 
 * nor may Indiana University or Community Grids Lab or NaradaBrokering appear
 * in their name, without prior written permission of ARTI.
 * 
 *
 * Indiana University provides no reassurances that the source code provided 
 * does not infringe the patent or any other intellectual property rights of 
 * any other entity.  Indiana University disclaims any liability to any 
 * recipient for claims brought by any other entity based on infringement of 
 * intellectual property rights or otherwise.  
 *
 *LICENSEE UNDERSTANDS THAT SOFTWARE IS PROVIDED "AS IS" FOR WHICH NO 
 *WARRANTIES AS TO CAPABILITIES OR ACCURACY ARE MADE. INDIANA UNIVERSITY GIVES
 *NO WARRANTIES AND MAKES NO REPRESENTATION THAT SOFTWARE IS FREE OF 
 *INFRINGEMENT OF THIRD PARTY PATENT, COPYRIGHT, OR OTHER PROPRIETARY RIGHTS. 
 *INDIANA UNIVERSITY MAKES NO WARRANTIES THAT SOFTWARE IS FREE FROM "BUGS", 
 *"VIRUSES", "TROJAN HORSES", "TRAP DOORS", "WORMS", OR OTHER HARMFUL CODE.  
 *LICENSEE ASSUMES THE ENTIRE RISK AS TO THE PERFORMANCE OF SOFTWARE AND/OR 
 *ASSOCIATED MATERIALS, AND TO THE PERFORMANCE AND VALIDITY OF INFORMATION 
 *GENERATED USING SOFTWARE.
 */
package cgl.narada.transport.niotcp;

import java.net.Socket;
import java.nio.channels.SocketChannel;

import cgl.narada.transport.Link;
import cgl.narada.transport.MonitoredLink;
import cgl.narada.transport.TransportDebugFlags;
import cgl.narada.transport.TransportException;
import cgl.narada.transport.TransportHandler;

/**
 * This is a NIOTCP implementation of the Link interface. Say we are trying to
 * establish a communication from node A to node B. To create links one needs
 * following properties to be specified.
 * <li><b>hostname</b>: This is the hostname on which the node B's process is
 * running.
 * <li><b>portnum</b>: This is the port number on which node B accepts link
 * creation requests from other nodes. In other words, the <i>NIOTCPServerPort
 * </i> specified to the NIOTCPChannelFactory at node B is equal to portnum.
 * 
 * @author Shrideep Pallickara $Date$ $Revision$
 */

public class NIOTCPLink extends MonitoredLink implements Link,
    TransportDebugFlags {
    private String linkId;

    private Object naradaBrokeringId;

    private String linkType = "niotcp";

    private boolean secure = false;

    private String securityInformation = "Communication on this link is not encrypted";

    private boolean connectionLost = false;

    private boolean linkClosed = false;

    private String moduleName = "NIOTCPLink: ";

    private SocketChannel sc;

    private NIOTCPSenderThread sender;

    private NIOTCPReceiverThread receiver;

    private NIOTCPLinkFactory niotcpLinkFactory;

    private TransportHandler transportHandler;

    public NIOTCPLink(SocketChannel sc, NIOTCPLinkFactory niotcpLinkFactory)
        throws TransportException {
        try {
            this.sc = sc;
            Socket socket = sc.socket();
            socket.setKeepAlive(true);
            // String _host = socket.getInetAddress().getHostName();
            String _host = socket.getInetAddress().toString();
            int _port = socket.getPort();
            String _key = "niotcp://" + _host + ":" + _port;
            linkId = _key;
            this.transportHandler = niotcpLinkFactory.getTransportHandler();
            receiver = new NIOTCPReceiverThread(sc, this);
            // receiver.setLinkId(_key);
            sender = new NIOTCPSenderThread(sc, this);

            this.niotcpLinkFactory = niotcpLinkFactory;

            if (NIOTCPLink_Debug) {
                System.out.println(moduleName + "Initialization complete");
            }

            // receiver.start();
            sender.start();
        } catch (Exception e) {
            throw new TransportException(moduleName + e);
        }
    }

    public void startLinkServices() {
        receiver.start();
    }

    /** The method used to send data over a communication link */
    public void sendData(byte[] data) throws TransportException {
        if (NIOTCPLink_Debug) {
            System.out.println(moduleName + "Sending data");
        }
        sender.sendData(data);
    }

    /**
     * The method used to send data over a communication link, this method also
     * includes information regarding the type (audio/video/xml-attachments
     * etc.) of the data encapsulated within the data stream. Using this
     * information links can optimally flush/send data across the link
     */
    public void sendData(byte[] data, String dataType)
                                                      throws TransportException {
        sender.sendData(data, dataType);
    }

    /** Sets the Id of the communication link */
    public void setLinkId(String stringId) {
        this.linkId = stringId;
        receiver.setLinkId(stringId);
    }

    /** Retrieves the String based id of the link */
    public String getLinkId() {
        return linkId;
    }

    /** The Naradabrokering Id of the node this link interacts with */
    public void setNaradaBrokeringId(Object brokeringId) {
        naradaBrokeringId = brokeringId;
    }

    /** Returns the NaradaBrokeringId associated with this link */
    public Object getNaradaBrokeringId() {
        return naradaBrokeringId;
    }

    /** Returns the type of the communication link */
    public String getLinkType() {
        return linkType;
    }

    /**
     * Sets the conditions under which communication protocols need to be
     * switched and the transport link that it should be switched to under the
     * condition. Multiple constraints can be set signifying migration to
     * different protocols.
     */
    public void setLinkMigrationConstraint(String constraint, String linkType) {
        /** NBNI */
    }

    /**
     * Check the status of the communication link at intervals specified in the
     * argument of this method
     */
    public void setLinkStatusInterval(long interval) {
        /** NBNI */
    }

    /**
     * Set the amount of time after which resources associated with this link
     * need to be garbage collected. A value of '0' indicates that this link
     * needs to be active at all times.
     */
    public void setKeepAliveTime(long keepAliveTime) {
        /** NBNI */
    }

    /**
     * Garbage collect resources associated with this link. Sockets need to be
     * closed and any resources associated with communication, needs to be
     * garbage collected
     */
    public void closeLink() {
        linkClosed = true;
        try {
            while (sc.socket().isConnected()) {
                sc.socket().shutdownInput();
                sc.socket().shutdownOutput();
                sc.socket().close();

            }
            sc.close();
            System.out.println(moduleName + "Closed socket connection to "
                + sc.socket());
        } catch (Exception ioe) {
            if (NIOTCPLink_Debug) {
                System.out.println(moduleName + "Trapping exception " + ioe);
            }
        }
        receiver.releaseResources();
        /** Releasing both */
        sender.releaseResources();
        niotcpLinkFactory.reportLinkLoss(this);
    }

    /** Indicates weather communication is encrypted on this link */
    public boolean isSecure() {
        return secure;
    }

    /**
     * Information pertaining to the security strategy adopted for this
     * communication link
     */
    public String getSecurityInformation() {
        return securityInformation;
    }

    /**
     * If the senderNotification is false, it implies that the detection of
     * connection loss has been reported by the receiver thread. Proceed to
     * garbage collect the sender thread. If the boolean variable is true, it
     * implies that the receiver thread has to be garbage collected.
     */
    public void processLossOfSocketConnection(boolean senderNotification) {
        if (linkClosed) {
            /** No need to do further processing */
            return;
        }

        if (connectionLost) {
            /**
             * The loss was connection has been detected earlier, and the
             * associated garbage collection operations are being performed
             */
            return;
        }
        closeLink();

        /*
         * if (senderNotification) { System.out.println(moduleName + "Connection
         * loss reported by NIOTCPSender"); receiver.releaseResources(); } else {
         * System.out.println(moduleName+ "Connection loss reported by
         * NIOTCPReceiver"); sender.releaseResources(); } connectionLost = true;
         * niotcpLinkFactory.reportLinkLoss(this);
         */
        System.out.println(moduleName
            + "Processing of communication loss on link [" + linkId
            + "] complete");
    }

    public TransportHandler getTransportHandler() {
        return transportHandler;
    }

}
